This invention relates to a device and method for transferring fluid, especially for venting and/or priming fluid transfer and/or processing systems. The present invention is particularly useful in the administration of parenteral fluids, e.g., drugs, nutrients, hydration solutions, and/or transfusion products such as blood components.
Many fluid transfer systems such as fluid processing systems function more efficiently if they can be at least partially purged of air or gas before use. For example, it may be desirable to prime a fluid transfer system, e.g., to displace or remove air from one or more devices and/or tubes in the system to allow them to be filled with liquid before continuously operating the system. Since pockets of air or gas can block or slow the flow of liquid, minimizing or eliminating the presence of air or gas can allow the liquid to flow more quickly through the system.
Additionally, some transfer systems, e.g., for administering fluid to a patient, should minimize or prevent air or gas from passing beyond a certain location in the system. For example, some intravenous (IV) systems include a drip chamber or a bubble trap to capture air or gas so that it will not be administered to the patient. The drip chamber can also be used to allow the operator of the system to monitor the rate at which the fluid is administered. For example, the operator may observe the drip chamber to ensure that the patient is receiving the liquid at a given rate, e.g., a rate of so many drops of liquid per minute. If desired, the rate can be changed and the new rate can be monitored by observing the rate at which the drops of liquid pass through the chamber.
There are drawbacks to conventional fluid transfer systems. For example, some systems for administering transfusion products require a labor intensive effort by the operator of the system. Illustratively, when transfusing blood or blood products, especially when filtering and administering blood at the patient""s bedside, the operator of the system may have to start the flow of blood from the source bag with the drip chamber initially inverted until the drip chamber is about ⅔ full. Then the partially filled drip chamber is placed in the upright position and the system is primed. After the system is primed, blood can be administered, and the rate monitored through the drip chamber.
The operator must carefully monitor the initial filling of the inverted drip chamber, since overfilling the chamber leads to difficulties in monitoring the drip rate. For example, a high level of fluid in the chamber can provide insufficient space for a drop to form before it contacts the fluid in the chamber, making it difficult to count drops. On the other hand, underfilling the chamber increases the possibility that air will pass through the chamber, with possibly adverse consequences for the patient.
Accordingly, there is a need in the art for a device and method that provides for efficient priming of a fluid processing system, e.g., that allows a drip chamber to be filled to a desired level without a labor intensive effort. In particular, there is a need in the art for a xe2x80x9clevel settingxe2x80x9d drip chamber, that automatically vents air or gas, without overfilling.
The present invention provides for ameliorating at least some of the disadvantages of the prior art. These and other advantages of the present invention will be apparent from the description as set forth below.
In accordance with an embodiment of the present invention, a device for use in a fluid transfer system is provided that vents gas, without overfilling with liquid. Illustratively, gas can be vented from a flow metering device such as a drip chamber, and the drip chamber can be filled to a desired level of liquid, wherein the amount of liquid in the chamber is less than the total liquid capacity of the chamber. In a more preferred embodiment, the device vents gas, and seals after venting, without overfilling with liquid.
In an embodiment, once fluid flow toward the device is initiated by the operator of the fluid transfer system, the device automatically vents gas and fills to a desired level, without operator involvement. For example, the operator does not need to squeeze and/or invert the device. Moreover, the device can be filled with liquid, and subsequently utilized during administration of the liquid, while keeping the device in an essentially upright position, and without allowing gas or air to enter the device through the vent.